End mill types

This topic has 10 replies, 7 voices, and was last updated 14 February 2012 at 10:13 by Nobby.

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13 February 2012 at 10:15 #84598
AlaninOz
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@alaninoz
My mill was supplied with what I believe is an Osborne chuck, end mills and slot drills screw into it and the collet locks down on them.

To date I have been using threaded P&N mills & drills, however I have been given some mills without a screw thread (plain shank). Are these suitable for use in my chuck without causing any damage? Will they slip in the chuck?

I am a complete learner ( king size L plates ) for milling but am having fun.

Alan
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13 February 2012 at 10:15 #5949
AlaninOz
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@alaninoz
13 February 2012 at 10:35 #84601
Jon
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@jon
Same as the Clarkson type which rely on the pip to stabilise and stop the cutters revolving.

In short, no it will slip.

One of three reasons i hate the things.
13 February 2012 at 10:40 #84602
John Stevenson 1
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@johnstevenson1
You can use these but because they reply on the threaded end hitting the centre stop before they tighten you will have to sacrifice a cutter and grind off just the thread portion.

Screw this in from the other end, centre outwards and then your plain shank cutters will be gripped as it tightens up.

Bit of a bodge but it does work.

John S.
13 February 2012 at 11:15 #84604
Ian S C
Participant
@iansc
I have a similar chuck, and I found a way to use the unthreaded cutters, I made a collet to fit the 5/8″ collet, this has a thread and center hole, and is bored to take the cutter. On the ctter there is a flat and next to this I fit a grub screw. I also can fit things like countersink bits.Ian S C
13 February 2012 at 11:26 #84607
Nobby
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@nobby
Hi Alan

I agree John it works fine . We called them dummy centres. So dig out some worn out cutters and use the ends

Nobby
14 February 2012 at 00:37 #84700
Ian S C
Participant
@iansc
Nobby, arn’t the shanks of end mills hardened, I thought they were?Ian S C

oups; I was thinking of ding it the way I do it which would require drilling it lengthwise, then drilling and tapping it through the side, but I see how you do it using same size end as the cutter, must try that, thanks. Ian S C

Edited By Ian S C on 14/02/2012 00:42:23
14 February 2012 at 03:36 #84704
AlaninOz
Participant
@alaninoz
Thanks everyone for the advice

I only have one broken mill — so far! It was 3 mm and I pushed too hard! So I will cut off the thread as suggested with a 1 mil blade in the angle grinder and try it when I damage or wear out ones with the same shank size.

My mill has #3 MT with drawbar, what alternative chuck type would you suggest to use with plain shank mills? I have seen some mills with a flat on the shank about 20 mm in, I guess for a grub screw or some other means to keep the shank from spinning although the ones I was given do not have a flat.

Alan
14 February 2012 at 07:59 #84706
Thor 🇳🇴
Participant
@thor
Hi Alan

For gripping plain shank end mills or slot drills, you can use ER collets. Most of these collets have a gripping range of 1mm (a 6mm collet would grip tooling with shanks from 6mm down to 5mm). You can get a wide variety of ER collet chucks, and you can buy the collet chuck from one source and collets from another.

Thor
14 February 2012 at 09:56 #84718
NJH
Participant
@njh
Hi Alan

Here are a couple of pictures of an adapter I made to fit mini mills in a Pozilock screwed collet. It works well.

Quick to make.

Yes you really need to be careful with those small cutters – I too know from experience!

Regards

Norman
14 February 2012 at 10:13 #84719
Nobby
Participant
@nobby
Hi Ian & Guys

They are hard I sliced them of using an elastic wheel on a surface grinder when I was at work. With the same wheel ground a screwdriver slot on the other side.Here is some of the cutter holders I made to screw on my mill drill. Am I drifting away from the thread again

Nobby

Nobby
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